Well, the Swahili coast is nowhere near the Nile/Mediterranean and it was quite advanced. But that was connected to the Arab world via trade and I think what you mean is did any African societies develop to a similar level of sophistication without influences from outside of Africa?
That's a complicated question that I'm not qualified to answer (Congo maybe?), but I'd point out that even in the ancient near east, trade and contact with foreigners preceded the development of civilization in those regions and European civilization especially owes a lot of its success to contact with outside civilizations. So the fact the most well-known African civilizations had regular trade contacts with Eurasia should not do much to diminish the accomplishments of those civilizations as such.
For example, it's possible that iron smelting began in the Sahel in Africa, and from there spread to the Near East/Mediterranean rather than the other way around which would mean that Africa entered the iron age well before the rest of the world. [1]
That's a complicated question that I'm not qualified to answer (Congo maybe?), but I'd point out that even in the ancient near east, trade and contact with foreigners preceded the development of civilization in those regions and European civilization especially owes a lot of its success to contact with outside civilizations. So the fact the most well-known African civilizations had regular trade contacts with Eurasia should not do much to diminish the accomplishments of those civilizations as such.
For example, it's possible that iron smelting began in the Sahel in Africa, and from there spread to the Near East/Mediterranean rather than the other way around which would mean that Africa entered the iron age well before the rest of the world. [1]
1. https://en.wikipedia.org/wiki/Iron_metallurgy_in_Africa